Astellas Pharma Inc. (4503)’s drug to treat overactive bladder has side effects including increased blood pressure that need to be considered when weighing whether the medicine should be approved, U.S. regulators said. The medicine, mirabegron, also increased heart rate and was associated with hypersensitivity reactions ranging from painful rash to anemia, the Food and Drug Administration said today in a report ahead of an April 5 meeting of advisers on the drug. Overactive bladder -- the strong, sudden urge to urinate -- affects 42 million people in the U.S., Nancy Martin, medical director of scientific and medical affairs for Tokyo- based Astellas, said by telephone. Mirabegron is the first in a new class for the condition, according to Astellas.